I managed to remove the feed icon from my address bar, but if I simply call up rss.php in a browser I can subscribe to the feed. Is it safe just to rename this file, or what is the best way to turn the existing feed off, if someone's already subscribed?

I temporarily commented out the relevant portion of core.theme.php to remove the icon from the address bar, but I don't really want to be messing with core files like that do I? Is there an "approved" way of doing this, or is that it?